Share Virtual Network between Resource Groups

Q. How do I share a virtual network in one Azure Resource Group to another Resource Group?

A. A resource can only exist in a single Resource Group which means a single Virtual Network cannot be added to multiple Resource Groups but it does not need to be. VMs in a different Resource Group from where the Virtual Network resource is located can still use the Virtual Network providing there are no permissions restrictions. The only requirements are:

If you cannot see a desired Virtual Network when creating a VM check the VM is in the same region as the network and if it is check the permissions on the virtual network to ensure it has not been restricted via Role-based Access Control.